The vast majority of games do support it on day 1 though. To me cut scenes aren't that big of a deal and most 21.9 users over look it as when in actual game, that is where the 21.9 benefits really shine and why I and most others on the likes of here have bought into 21.9 as 16.9 gaming just feels so squashed especially in certain games where you have no FOV slider i.e. the division.
I don't think we'll never see 21.9 pre-rendered cut scenes unless the developers themselves get 21.9 screens or use in game engine to do the cut scenes like in far cry primal and some other ubi games. Not to mention their main priority are consoles, which aren't capable of 21.9 at all and most people only have the choice of 16.9 TVs so yeah pre-rendered 21.9 cut scenes won't happen any time soon imo.
It doesn't cost developers anything to implement the support. If some guy can get a fix on the day of release then I think multi million dollar game companies with a whole team can manage it
For cutscenes, they could just produce/render them to be 21.9 like 90% of films and then have black bars at the top and bottom of 16.9 displays to give that "cinematic" experience.
We will have to see about 4k 16.9 vs ultrawide, 4k has been around for far longer than 21.9 and cheaper with more choice too. Personally I don't see 4k as a viable resolution even with the likes of a 1080ti as whilst it might perform well in current games today, what about next years games that will be even more demanding? We will be back to having to turn down settings to be able to hold 50+ FPS 90% of the time.
Only 2 games in the last year, which I am aware of that don't have proper support at all are overwatch and resident evil 7 (fixed with a 3rd party tweak)
I have been using 21.9 for 4+ years now and have played more than my fair share of games.
1-2 years - very patchy, had to rely on so many fixes and they were slow because it was pretty much the new kid on the block (only other choice was a few other 29" monitors and only one 34" 1440 monitor)
3rd year - big increase in users, official support was still patchy but with flawless widescreen and more people getting 21.9 monitors, fixes were available on the day of release
4-5th year - very good support overall and I haven't had to launch flawless widescreen or mess about with any config files
But as you know, I'm not bothered by cutscenes being in 16.9, the HUD/UI being stuck in 16.9 bothers me far more!
Thankfully this is becoming a lot better too and surprisingly, it is ubisoft that are best for it...
You have to remember 4k is just a resolution at the end of the day with a fancy marketing spin put on it, it is not tied down to 16.9, you can have "4k" res. for 21.9 displays too.
EDIT:
Some news on upcoming HDR panels:
Personally I will avoid any type of edge lit local dimming monitor as it creates issues with certain scenes like the following:
